Add server deployment support with Essentia

- Add install-server.sh for easy deployment on Linux servers
- Update Dockerfile to auto-detect architecture (x86_64/ARM64)
- Add deploy.sh for remote deployment
- Update requirements.txt with Essentia support notes

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

backend/requirements.txt

@@ -15,12 +15,8 @@ soundfile==0.12.1
 audioread==3.0.1
 mutagen==1.47.0
 
-# Optional: Essentia for genre/mood/instrument classification
-# Note: essentia-tensorflow not available on PyPI for all platforms
-# Uncomment if you can install it (Linux x86_64 only):
-# essentia==2.1b6.dev1110
-# For manual installation: pip install essentia
-# Or build from source: https://github.com/MTG/essentia
+# Essentia for genre/mood/instrument classification
+# Note: Essentia is installed separately in Dockerfile from official wheels
 
 # Scientific Computing
 numpy==1.24.3